Lubricating greases thickened with 3-nu-aryl-carbamyl-2-hydroxy-1-naphthyleneazoarenes



LUBRICATING GREASES THICKENED WITH 3-N- ARYL CARBAMYL 2 HYDROXY 1 NAPH- THYLENEAZOARENES Joseph F. Lyons, Wappingers Falls, and Norman R. Odell, Fishkill, N. Y., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application December 28, 1956 Serial No. 631,031

8 Claims. (Cl. 25249.6)

O H il-Ik-Ar' wherein Ar and Ar are aryl groups, preferably phenyl or naphthyl groups, or substituted aryl groups, and R represents hydrogen or one or more substituent radicals. Substituents represented by R, and which may also be present in the aryl groups represented by Ar and Ar, are preferably substantially neutral, non-salt forming groups such as, for example, alkyl, aryl, alkaryl, aralkyl, ether, ester, aldehyde, amino, hydroxy, nitro groups and halogens.

The compounds of the above class are high melting solids, having the properties of pigments. They are either commercially available or readily produced by well known methods involving coupling diazotized arylamines with arylides of 3-hydroxy-2-naphthoic acids (Naphthol AS). Particularly suitable compounds which are commercially available include the following:

3-N-phenylcarbamyl-Z-hydroxy-1-naphthaleneazo-2'-methoxy- 5'-nitrobenzene lTIOz 3-N-m-nltrophenylcarbamyl-2-hydroxy-1- aphthyleneazo-2- methoxy-5'-nitrohenzene Patented Sept. 9, 1958 3-N-o-ethoxyphenylcarbamyl-2-hydroxy-l-naphthyleneazo-Z'- methyl-5 -cl1lor0benzene 3-N-o-methylphenylcarbamyl-Z-hydroxy-l-naphthyleneazo-2'- Additional examples of suitable compounds of this class which may be mentioned include the following: 3- N a naphthylcarbamyl 2 hydroxy 1 naphthalene azobenzene; 3 N p ethylphenylcarbamyl 2 hydroxy 6,7 dichloro l naphthaleneazo 2',5-dichlorobenzene; 3 N phenylcarbamyl 2 hydroxy 5- nitro 1 naphthaleneazo a naphthene; and 3 N- o chlorophenylcarbamyl 2 hydroxy 5 methyl 7- nitro 1 naphthaleneazo 2',4,6-trimethylbenzene.

The above compounds may be employed either in pure such as up to about 10 perby weight of such thickening of the composition.

The grease preparation may be carried out by merely mixing together the thickener and any additives employed with the lubricating oil, employing any convenient means such as milling in a colloid obtain a thorough dispersion of a thickener and additives in the lubricating oil base. The mixing may be carried out at ordinary temperatures or at elevated temperatures up to about 300 ficultly soluble additives. The lubricating oils employed may be any suitable F. in order to dissolve difoils of lubricating characteristics, including the conventional mineral lubricating oils, synthetic oils obtained by various refinery processes, such as cracking and polymerization, and other synthetic oleaginous compounds. Suitable mineral oils include parafiinic and naphthenic oils having viscosities in the range from about seconds SU at F. to about 225 seconds SU at 210 F., and preferably those having viscosities in the range from about 100 to about 600 seconds SU at 100 F. For preparing high temperature greases, synthetic oils of various types, including particularly silicone oils and polyesters are preferably employed. Such oils may very advantageously comprise from about 50 up to 100 percent of the oil component of the grease, the remainder being mineral oil or other oil of a different type.

A particularly suitable class of synthetic polyester oils materials will be pres-.

mill or in a paint mill toare those disclosed by R. T. Sanderson in U. S. 2,628,974, obtained by reacting dibasic aliphatic acids with glycols and end-blocking the reaction products with monohydric aliphatic alcohols or monocarboxylic aliphatic acids. The preferred materials of this character are products obtained by reacting monoor polyalkylene glycols with dicarboxylic acids and monohydric alcohols, represented by the formula wherein R is an aliphatic hydrocarbon or an aliphatic ether group containing from 4 to 12 carbon atoms, R; and R arealiphatic hydrocarbon groups containing from 1 to 12 carbon atoms andx is an integer from 1 to 5.

The silicone oils are compounds having the general wherein R, R R R R and R represent alkyl, aryl, alkaryl or aralkyl groups, which may be the same or different, and n is a number sufficient to give a viscosity in the lubricating oil range to the compound, preferably a viscosity in about the range from about 100 to 600 pounds SU at 100 F. Sui-table compounds of this type include dimethylsilicone polymer, diethylsilicone polymer, methylcyclohexylsilicone polymer, diphenylsilicone, methylphenylsilicone polymer, methylethylsilicone polymer, methyltolylsilicone polymer, etc. These materials may be prepared by various methods, including hydrolysis of hydrolizable organic-substituted silanes, as described for example in U. S. 2,410,346 and U. S. 2,469,888.

Additives of the usual types may be employed in these greases, such as, for example, oxidation inhibitors, corrosion inhibitors, tackiness agents, extreme pressure agents, etc. Suitable oxidation inhibitors include particularly those of the amine type, such as diphenylamine, a-naphthylamine, fi-naph'thylamine, p-phenylenediamine and N,N-diphenyl-p-phenylene diamine. A compound of this type may be present in amounts from about 0.5 to about 5 percent by weight, based on the weight of the composition. An oil-soluble phosphorus acid ester may very advantageously, be employed in conjunction with an amine of this type in amounts from about 1 to percent by weight based on the weight of the composition, to serve as a solvent and carrier for the amine. Also, additional thickening agents may be employed in minor amounts, such as other finely divided solids of various types and metal soaps of high molecular weight fatty acids, such as are commonly employed in lubricating greases.

Greases which are representative of the-greases of this invention are described in the following examples:

EXAMPLE 1 A grease was prepared having the following-composition in percent by weight:

Solid thickener 20 Lubricating oil 80 The solid thickener employed was the substantially pure compound 3-N-m-nitrophenylcarbamyl-2-hydroxy-1- naphthaleneazo-2-methoxy-5'-nitrobenzene in finely di superior lubricating properties generally, including excellent shear stability, oxidation resistance, and water resistance, as shown by the following tests.

Dropping point, "F 420 Working stability:

ASTM Penetration at77 F.-

After 60 strokes 351 After 100,000 strokes 341 ASTM bomb oxidation test: hours at 210 F. lbs. pressure drop Dynamic water resistance test: percent loss 6.3 Water absorption test:

Water absorption, percent 100+ ASTM worked penetration after test 322 EXAMPLE, 2

A grease was prepared having the following composition in percent by weight.

Solid, thickener 25.0 Diphenyl p-phenylene diamine 1.0 Tricresyl phosphate 3.0 Lubricating oil 71.0

ratio respectively, and consisted predominately of the compound The grease preparation was caried out as described in Example 1, employing a grease mixture consisting of 300 grams of the thickener, 12 grams of the amine inhibitor, 36 grams of tricresylphosphate, 795 grams of the synthetic:ester and 57 grams of. the mineral lubricating oil.

The amine inhibitor was added to the mixture in solution in the tricresylphosphate.

The following tests were obtained upon this grease.

ASTM worked penetration after test 269 Copper corrosion, MIL-L-3545, 24 hours pass High temperature performance test: hours at The high temperature performance test of the foregoing table is a test for determining the performance characteristics of greases in anti-friction bearings at elevated'temperatures and high rotative speeds. The test unit consists essentially of a steel spindle supported on ball bearings in an electrically heated housing and driven by an electric motor connected into an electric circuit containing a low amperage fuse 0.1 ampere below that required for full load running. The bearings are Norma- Hoffman ABEC No. 3 grade, and are mounted on a spindle approximately 5 /8 inches apart. A thrust load of 17.5 pounds is appliedtothe bearings. One bearing is used for test purposes and the second bearing, which sists of operating the test bearing for twenty-four hours at 10,000 R. P. M. and at a temperature of from 250 F. to 450 F. followed by a shutdown and cooling period of two hours, and repeating this cycle until the lubricant fails, which is indicated by rupture of the low amperage fuse in the motor circuit. In carrying out the test at 400 F. or above, Marlin Rockwell special heat treated high speed tool steel bearings with silver plated bronze retainers are used. In starting up the test, three grams of the test grease are charged to the test bearing and worked into and around the races and balls. The bearing is next rotated both clockwise and counterwise for one minute each at 200 R. P. M. and assembled into the test unit. The heaters and the motor are then started and the test bearing brought up to the test temperature as rapidly as possible, which requires 1.0 to 1.25 hours, while the spindle is rotated at a speed of 10,000 R. P. M. After 24 hours of operation the heaters and motors are shut 011 for two hours, during which the temperature of the test bearing drops to a minimum of 120130 F. The total hours of operation excluding the two hour shutdown periods, to the failure point is recorded as the hours to failure.

The high temperature performance life of the grease of this invention in the above test was far in excess of that obtainable in the conventional soap thickened greases, which are ordinarily unsuitable for use at temperatures above about 300 F. In addition, it was considerably higher than that obtainable by employing solid thickeners of the prior art in lubricating oils of the ester .type. For example, a copper phthalocyamine thickened grease of the same composition otherwise ran for only 119 hours at 400 F. in this test.

EXAMPLE 3 As an additional example of the greases of this invention, a grease was prepared employing as the thickening agent the compound 3-N-o-methylphenylcarbamyl-Z- hydroxy 1 naphthaleneazo 2' nitro 4' methylbenzene. This was a commercial pigment having a particle size of about 0.1 to 0.2 by 1.5 microns and a measured surface area of 76 square meters per gram. The grease consisted of 30 percent by weight of this material in a refined parafiinic distillate oil having a viscosity SU at 100 F. of about 335 seconds.

The grease preparation was carried out by mixing together the oil and thickener and finishing with one pass through a Premier colloid mill at 0.002 inch clearance. A smooth glossy grease was obtained having an ASTM unworked penetration of 321. It had a high dropping point of over 500 F. and very good shear stability, as shown by an ASTM penetration of 352 after 60 strokes and of 330 after 100,000 strokes in the ASTM Worker Test.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A lubricating grease consisting essentially of a lubricating oil thickened to a grease consistency with a compound selected from the class consisting of 3-N-arylcarbamyl-2-hydroxy-1-naphthaleneazoarenes and substituted derivatives thereof which are free from oil-solubilizing groups and from salt-forming'groups.

2. The composition according to claim 1 wherein the said lubricating oil comprises in major proportion at least a dicarboxylic acid polyester.

3. The composition according to claim 1 wherein the said lubricating oil is a silicone polymer.

4. A lubricating grease consisting essentially of a lubricating oil thickened to a grease consistency with 3-N-mnitrophenylcarbamyl 2 hydroxy 1 naphthaleneazo- 2'-methoxy-5'-nitrobenzene.

5. A lubricating grease consisting essentially of a dicarboxylic acid polyester having a viscosity in the lubricating oil viscosity range thickened to a grease consistency with about 15 to 35 percent by weight based on the weight of the composition of 3-N-m-nitrophenylcarbamyl 2 hydroxy 1 naphthaleneazo 2' methoxy-5'-nitrobenzene.

6. The composition according to claim 5 containing about 0.5 to 5.0 percent by weight of an amine oxidation inhibitor.

7. A lubricating grease consisting essentially of a lubricating oil thickened to a grease consistency with a compound selected from the class consisting of 3-N-arylcarbarnyl-Z-hydroxy-l-naphthaleneazoarenes and substituted derivatives thereof wherein the substituent groups are chosen from the class consisting of lower alkyl groups, lower alkoxy groups, halogens and the nitro group.

8. A lubricating grease consisting essentially of a lubricating oil thickened to a grease consistency with 3-N-omethylphenylcarbamyl 2 hydroxy 1 naphthaleneazo- 2-nitro-4-methylbenzene.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Manufacture and Application of Lubricating Greases- BonerReinhold Pub. Corp., N. Y., 1954, pages 690-691. 

1. A LUBRICATING GREASE CONSISTING ESSENTIALLY OF A LUBRICATING OIL THICKENED TO A GREASE CONSISTENCY WITH A COMPOUND SELECTED FROM THE CLASS CONSISTING OF 3-N-ARYLCARBAMYL-2-HYDROXY-1-NAPHTHALENEAZOARENES AND SUBSTITUTED DERIVATIVES THEREOF WHICH ARE FREE FROM OIL-SOLUBILIZING GROUPS AND FROM SALT-FORMING GROUPS. 